Lockout and alarm device for circuit breakers



Feb, 1, 1949. H H LAWSQN 2,460,758

LOCKOUT AND ALARM DEVICE F-QR CIRCUIT BREAKERS Filed March 25, 1946 Fig.I.

His Attorney.

Patented Feb. l, 194

LOCKOUT AND ALARM DEVICE FOR CIRCUIT BREAKERS Harold H. Lawson,Philadelphia, Pa., assignor to General Electric Company, a corporationof New York Application March 23, 1946, Serial No. 656,568

(Cl. f77-311) 5 Claims. 1

My invention relates to improvements in lockout and alarm devices forcircuit breakers and more particularly for circuit breakers which areprovided with automatic tripping means for efecting their opening underabnormal conditions.

Circuit breakers have been provided with alarm switches so arranged asto effect the ringing of a bell, the lighting of a lamp, the operationof an annunciator drop and the like when tripped automatically. Thearrangements with which I am familiar, however, are unsatisfactory. Theaddition of a manually operated cutoff switch in the alarm circuit toopen it without reclosing the circuit breaker is unsatisfactory because,if an operator upon reclosing a circuit breaker, failed to restore themanually operated switch at the same time to correspond to the circuitbreaker closed position, then an erroneous indication would bepresented. This discrepancy between the circuit breaker closed positionand alarm indication of circuit breaker open position might readilyresult in damage to both apparatus and personnel. Also, with either ofthe foregoing arrangements, an alarm is given whether the circuitbreaker is tripped automatically or manually. Moreover, arrangementswith which I am familiar are not economical because of the amount ofwiring and other features involved.

An object of my invention is to provide an improved lockout and alarmdevice for circuit breakers so that after being automatically trippedthe circuit breaker cannot be reclosed before the alarm indication ofcircuit breaker open position is cleared. Another object of my inventionis to provide an improved lockout and alarm device f which is relativelysimple in structure and operation and which Will selectivelydifferentiate be tween automatic tripping and manual tripping of thecircuit breaker. Still another object of my invention is to provide animproved lockout and alarm device which is readily adaptable to variouscircuit breakers and especially the tripping means associated therewith.A. further object of my invention is to provide an improved automaticcircuit breaker lockout and alarm device which is particularly adaptedfor manually resetting Without any possibility of blocking orinterfering with the operation or Calibrating of the automatic trippingmechanism of the circuit breaker. These and other objects of myinvention will appear in more detail hereinafter.

In accordance with my invention, I provide in a manually reset lockoutand alarm device for a circuit breaker provided with a tripping elementand automatic actuating means therefor. means Cal for maintaining thetripping element in the tripped position only when operated thereto bythe automatic tripping means in consequence of the operation thereof.For this purpose, I provide a lockout member biased for movement from aninitial position to a nal position into holding engagement with thecircuit breaker tripping element to prevent reclosing of the circuitbreaker only after it has been automatically tripped. To permitreclosing of the circuit breaker, I provide manual actuating meansadapted to be operated to return the lockout member against the biasthereon to the initial position and means including a latch for holdingthe lockout member in the initial position and arranged to be releasedonly upon operation of the circuit breaker automatic tripping meanswhereby to effect movement of" the lockout means to its nal position.Also in accordance with my invention, I provide the lockout member withalarm means to provide an indication of the automatic tripping of thecircuit breaker.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying drawing, and itsscope will be pointed out in the appended claims.

In the accompanying drawing, Fig. l is a side elevation illustrating anembodiment of my invention as applied to a circuit breaker, shown onlyin part, with the parts presented in the circuit breaker closedposition, and Fig. 2 is a side elevation similar to Fig. l with theparts presented at the moment of tripping the circuit breaker.

For the purpose of illustrating my invention, I have shown an embodimentthereof as applied to a circuit breaker secured to a base I ofinsulating material and shown only in part as comprising a supportingframe 2. As far as my invention is concerned, the particular type ofcircuit breaker is immaterial, but I have further illustrated thecircuit breaker as including a tripping mechanism comprising a trippingshaft or element 3 which is supported in the frame 2 and is providedwith a tripping arm 4. The shaft 3 is biased to the holding positionshown in Fig. l by a spring 5. For actuating the tripping shaft 3 to thereleasing position, the circuit breaker is also shown as provided withautomatic electroresponsive actuating means comprising a U- shapedmagnet 6, an energizing winding 1 and an armature 8. The magnet 6 issecured to the base I by suitable means such as screws 9. For currentresponse, the Winding 1 is connected between the lower stud I0 of thecircuit breaker and the lower contact block H so as to be in seriesrelation with the circuit through the circuit breaker. The armature 8 ispivotally supported at I2 in a bracket I3 which is shown as secured tothe magnet 6 and to a supporting bracket I4 suitably secured to thecircuit breaker frame 2. Also the armature 8 is biased to theunattracted position by suitable means, not shown, Which may beadjusted; asiwellfknown to gth'eart; for controlling the pickupv point'or response ofthe tripping means. to the tripping or releasing positionupon movement of the armature 8 from theun'attractedv position shown inFig. 1 to the attracted position' shown in Fig. 2, the armature isprovided with.

a hook-shaped extension lwhichisarranged to engage the lower end of atripping lever I6 pivotally mounted at in a bracket I8 secured to thecircuit breaker frame 2. The 'leverIE' is provided" with a curved upperportion I3 which is arranged upon clockwise movement of the lever I6 toengage the tripping arm 4 and to turn it Avcounterclockwise tothe'releasing' 'position shown in Fig.

2.' For" adjustment purposes,v a screw 20 is.

mountedin theV bracket I8* for contact-with the lever I6 to'v establishits' non-tripped position shown in Fig. 1.

In accordance with my invention, I provide means for maintaining thecircuit .breaker tripping shafft or element 3 in the tripped position,shown in Fig. 3, after actuation thereto in consequence of the operationof the. electro-responsive tripping means. As shown, this mean-s is alockout member 2| which is mounted Ifor movefrom an initial position,shown in'Fig. 1,

to a nalposition, shown in Fig. 2, into holding :1

engagement with the tripping shaft 3 through the medium of 'an arm 22suitably secured thereto as-by abolt 23. Also', in accordance with myinvention, the lockout member 2| functions as'an alarm control orswitching member and is mounted for' .rectilinear movement in asuitably' shapedbl-ock 2 4--v of insulating material secured to ythesupporting bracket I4 as by a bolt' 25. Themember 2| is biased tothetrip element holding or na'l position by suitable mean's'such` as aspring 23 which,V as shown, is aroundthe member between the top of the.block 24 and nuts 21 on the member foradjus-tment purposes.-

InY the trip element holdingposition, lthe member 2I'isalsoV arranged tocompletethe circuit 28 of suitable alarm and indicating devices such asla' bell 29 and a lamp 3U. the member 2| is arranged to actua-tesuitable contact means such' as a movable contact 3|, which, as shown,is'resiliently supported on the member and is arranged to bridgestationary contacts 32 mounted on the block 24 andi provided`withterminals 33 to which the circuit conductors 28 are connected.For'energizing' the alarm circuit 28, a` suitable sourcev ofelectromotive vforce such as a battery 34 is provided;A

Further in accordance with my invention',.1

provide actuating means adapted. .to be operated toreturnthe lockoutmember 2| to the initial position yshown .in Fig. 1 agains-tthe bias ofthe spring 26' so that the tripping 'shaft 3 may'returnto vthe latchingposition shown `in Fig. 1 under the bias of the spring 5. As shown, thisactuating means comprises an element 35 which is connected'to thelockout member 2| for movement. simultaneously therewith and relativelythereto vand is movable in one direction to return' the member lto its,initialposition For vthis purpose;f the actuating I or .resettingelement' 35. which' is roughly U-shapedis pivoted'at 3`6jon Foractuating the tripping shaft 34 For this purpose,

the supporting bracket I4 and is also loosely pivotally connected to themember 2| by a pin 3l -on the member and projecting into a slot 38 inthe element so that it can have freedom of angular movement Withoutinterfering with the linear movement of the member.

For actuating the elementl 3511s adirection, yclockwise as viewedthe-drawing; tof` return the lockout member 2| to its initial position,I provide means such as a push rod 39 which, as shown, Yis linearlymovable from right to left as viewed in-FigZ-to engage the leg 4I) ofthe resetting' element 35 and turn it clockwise about its pivot 3E. Asshown, the. push .rod 39 is mounted on the supporting bracket I4 andbias-ed for movementfromleft to right away from the element .35 bysuitable means such as a spring 4|. Fore'ase' manipulation, the push rod39 is provided with a knob or handle 42.

For holding the resetting element 35 in a position to maintain thelockout member 2| in its initial position, I provide meansy which isarranged to be released upon operation ofY the electrore'sponsivetripping means whereby to eiectv movement' of the member to ilts nalortrip. holding. position under the actionvof the spring. 2li. 43"which,as shown, is mounted.on-aQslraftlv 44 arranged to turn about the samepivotal' axis' I2 as the armature' 8' does and -to' engage .the

leg-65' of the actuating element 35fasshown in Fig. l. On :the shaft 44,there is mounted'la'lever 43' having an arm 4i' extending outwardlyfroml the plane of thedrawinginto the path of movementof the armature 8'so'that upon movement' thereof to the' attracted position, the latch43'A is released to permit movement of the element' 33 and' the member2| under the bias' of the' spring' 2'6. For resetting'the latch43"to"the.hold2 `ing position, it may. be biased by suitable means suchas' a spring 48 attached'to the arm`4`i'v and'.

tothesupportingbracket i4. Also', I- have shown the shaft 44 as providedwith a counterbalancing weight 49'Lwh`ich tends to turn the shaftcounterclockwise" and to render it less susceptible to."

movementirom shocks. For establishing the 'de-k sired latfching; Iprovide an adjustable stop '50" which, as shown, `is monntedon thesupporting" bracket arm 46.'

Assuming 'now ythe parts positioned as shown inFig; 1 and: thatthecircuit breaker is closed',` then. theresetting `element 35 ismaintained'in the holding position againstthe bias of the' spring 25-'bythe'latch 43; Whencurrent flo-wsin the I4; in the path of movement ofthe winding lt'o Ian amount sufficient to `attract the 1 armature 8; thetripping. lever i3 will be engaged' by the hook-shaped V'extensionv i5on' the armattu'eand turned clockwise suiiiciently't'o rotate thetripping arm 4" to the releasing' position' Substantially against the'biasof'the spring 5. simultaneously therewith, the latch 43` is releasedfrom the arm 450i the resetting member 35sothat the lockout andoperating member 2|'A is free to move upwardly under the bias of thespringZii'l from the initial position shown in Fig. 1 tov the tripholding positionshown' in Fig'. 2. At the same time; th'ebridgingcontact 3l en.- gages the .stationary contacts 32 to complete the alarmcircuit 23' thereby lighting the lamp. 3|l'v and ringing' the'bell' 39,ifboth of these devices are provided.v As 'long as the lockout andalarm'member 2i remains .in the trip holding position in engagementwiththe arm 22`onthe tripshaft 3, the circuit breaker .cannot be re- Forthis purpose, I provide a latch` closed because the trip shaft is heldin a position such that it cannot be moved Ito the circuit breakermechanism holding position. Before the circuit breaker can be closed,the actuating element 35 must be rotated clockwise so that the latch 43can fall in behind the end of the arm 48. This clockwise movement of theactuating element 35 is effected by ypushing in on the knob 42 to engagethe arm 40 so that it can be rotated sufftciently to come into thelatching position, as shown in Fig. 1. With this arrangement, it will beobvious that before the circuit breaker can be reclosed the alarmindication, showing ythat the circuit is open after an automatictripping, must be annulled.

From the foregoing, it will be apparent to those skilled in the art thatdevices, embodying my invention, may be used on single pole ormulti-pole circuit breakers wherein all poles open when one pole istripped and only one device is necessary to accomplish the desiredresults where all poles trip. Moreover, as far as my invention isconcerned, it is immaterial whether the automatic tripping means iselectroresponsive, such as the overcurrent device illustrated, or ispressure or float operated or the like.

While I have shown and described my invention in considerable detail, Ido not desire to be limited to the exact arrangements shown, but seek tocover in the appended claims all those modifications that fall withinthe true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A manually reset lockout and alarm device for a circuit breaker tripmechanism having automatic tripping means, comprising an auxiliary latchreleased by said automatic tripping means, lockout means including amember held under control of said latch in an inactive position andhaving biasing means for moving said member therefrom upon release ofsaid latch to a lockout position for holding said mechanism to preventreclosure of the circuit breaker, alarm switching means operated by saidmember in said lockout position, and manual reset means for returningsaid member to said inactive position- 2. In a circuit breaker tripcontrol and alarm mechanism, a circuit breaker trip member having atripping positionfor opening the circuit breaker and preventingreclosure thereof, biasing means for biasing said trip member to aninactive position, automatic tripping means for moving said member tothe tripping position, a lockout member having biasing means for movingsaid lockout member to a lockout position for holding said trip memberin said tripping position thereof to prevent reclosure of the circuitbreaker, alarm switching means operated by said member in said lockoutposition thereof, a latch for holding said lockout member in an inactiveposition, means under control of said automatic tripping means forreleasing said latch, and manual reset means for returning the lockoutmember to said inactive position.

3. In a circuit breaker trip control and alarm mechanism, a circuitbreaker trip shaft rotatable to a tripping position for opening thecircuit breaker and preventing reclosure thereof, biasing means forbiasing said trip shaft to an inactive position, automatic trippingmeans for rotating said shaft to said tripping position, an arm on saidshaft, a movable lockout member having biasing means for moving saidlockout member to a lockout position in engagement with said arm to holdthe shaft in said tripping position and thereby prevent reclosure of thecircuit breaker, alarm switching means operated by said member in saidlockout position thereof, a latch for holding said lockout member in aninactive position, means under control of said automatic tripping meansfor releasing said latch, and manual reset means for returning thelockout member to said inactive position.

4. In a manually reset lockout and alarm device for a circuit breakerhaving a tripping shaft and automatic actuating means therefor, an armon said shaft, a member having biasing means for moving said member froman inactive position to a position for holding said arm in the trippedposition of said shaft, alarm switching means operated by said member inthe holding position thereof, control means for said member including apivotally mounted element connected with said member for pivotalmovement upon movement of said member between said positions, manualreset means for operating said pivotal element to return the member tothe inactive position and a latch for engaging said pivoted element tomaintain said member in its inactive position, said latch having amember operated by said automatic actuating means only upon operationthereof to trip the breaker for releasing said latch to effect movementof the biased member to said holding position.

5. In a manually reset lockout and alarm device for a circuit breakerprovided with a trip shaft having two arms thereon and automaticactuating means for one of said arms, a member having biasing means formoving said member from an inactive position to a position for engagtheother arm to hold the trip shaft in the tripped position, alarmswitching means, operated by the member in the holding position thereof,manual reset means including a pivotally mounted element connected withsaid member to return the member to its inactive position, a latchbiased into engagement with said pivoted member to hold said member inits inactive position, and a member operated by said automatic actuatingmeans for releasing said latch upon operation of the trip shaft to thetripped position.

HAROLD H. LAWSON.

REFERENCES orED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,848,853 Thumim Mar. 8, 19322,091,108 Sengebusch Aug. 24, 1937 2,227,506 Leonard Jan. 7, 1941

